Shooting games like "skins for $1" are solid for keeping things interesting, but you could also mix it up with some quick decision-making challenges. For example, call heads or tails before taking a shot, then flip a coin. If it lands on your call, you shoot at a smaller, more challenging target; if not, you take on a larger but further one.
And yeah, the classic "apple on the head" game still cracks me up—if you're brave enough for that kind of trust exercise.